I don't think it's true. Spark plugs are literally what they are...they just spark the air-fuel mixture in the combustion chamber. The air-fuel mixture just needs some spark, not necessarily a "powerful" spark so to speak.

Now spark plugs do have another important job, and that's to transfer out heat from the combustion chamber. They may be "colder" plugs compared to typical ones sold in auto parts stores. The "colder" the plug, the faster it transfers heat from the chamber. In general, this does nothing in terms of performance. This is more for engines that tend to run higher compression ratios (which cause hotter temps inside the cylinder) from the use of a turbocharger or supercharger, and this is to prevent pre-ignition.

Having said all this, I have no idea if this is the case for the E3 spark plugs you mentioned. I don't know why they are claiming increased power and fuel economy.

Scotty addresses at 3:49 in video.  In short, they don’t improve performance or mpg.

https://m.youtube.com/watch?v=eMc9RoTw90I